Cognomen Marsu (Marsu 
, Março 
, Marsvin) , in all the world, is a rare surname. The surname Marsu is characteristic of Mozambique, where it is a rare surname, Romania, and Portugal, where it is a very rare surname. Not in comparison with a country's population, it is the most numerous in India, Mozambique, and Indonesia. Likewise, Marsu is the forename as well as the last name.